Abnormal voltage on Y-delta transformer bank due to reversed connection

THE writer recently observed some abnormal voltage conditions on a Y-delta connected transformer bank which suggested the subsequent investigations described in this paper. The transformers were rated at 50 kw., 30 cycles, 12,000/2300 volts, and were Y-connected to a 22,000-volt, 623½-cycle line. This line was fed by a bank of 50,000/13,200 volt, tansformers Y-connected on the low tension side, and with grounded neutral as shown in Fig. 1.